Air charger



Jan. 4, 1949. A, w, EUR@ 2,457,863

AIR CHARGER Jan. 4, 1949.

A. w. BURKs AIR CHARGER 2 Sheets-Sheet 2 Filed Feb. 1, 1945 Hrw/wr: Mff/was.

Patented .ha 4, 1949 UNITED STATES PATENTOFFICE All CHARGERArthurW.Burh.DeoltIr,lii.. aloignortoecatur Pump Company, Decatur, lll.,a corporation of Application lobi-lary l, 1945. Serial No. 575,693

(Cl. 10S-6) l I Claims.

I'his invention relates to an air charger that is primarily adapted formaintaining pressure in a hydro-pneumatic tank such as is used in manywater supply systems.

In hydro-pneumatic water supply systems auch as disclosed in my issuedPatents Nos. 2,172,067 and 2,172,097, both dated September 5, 1939, theproblem is to maintain the desired pneumatic pressure above the level ofthe water in the supply tank so that the tank pressure may be maintainedat the desired point. Due to the absorption of air by the water and tothe loss of air, the tendency is for the pneumatic pressure to dropduring continued use of the system. A number of different devices,including those of my issued patents, have -been devised for supplyingair'to the hydro-pneumatic tank in accordance with the pressure in thetank and in response to the operation of the pump that supplies the tankwith water.

The present invention' relates to a novel and improved air chargermechanism for maintaining the pneumatic pressure within ahydro-pneumatic supply tank. The air charger of my invention operates inresponse to the pressure in the hydro-pneumatic tank and also inresponse water pump supplying the tank, when such pump water is drawnfrom the chamber and is replaced by air admitted through an air intakevalve. A float valve for controlling the iiow of water through theeductor to the intake side of the pump is actuated by a float withinsaid chamber so as to shut off said flow when the chamber becomessubstantially lled with air. Thereafter, the continued flow of waterinto the eductor passes into the chamber to expel the charge of air backinto the tank.

The air charger of my invention thus acts each time the pump is startedup, and as frequently as necessary while the pump continues to operate,to introduce a charge of air into the hydro-A pneumatic tank if thepressure therein is below a predetermined point. If no air is needed inelevation.

the hydro-'pneumatic tank to make up for losses, 5

2 then no new charge of air is delivered into the tank. but air ismerely withdrawn from the tank and expelled back into the tank. Thedevice is thus fully automatic and requires little, if any, attention.

It is therefore an important object of this invention to provide anautomatically operating air charger for maintaining the desiredpneumatic pressure in a hydro-pneumatic tank of a water supply system,the air charger being responsive to the tank pressure and the suctioneifect produced by the operation of the water supply pump to introduce acharge of air into the hydro-pneumatic tank whenever said pump isoperated provided there is a deficiency of air pressure within the tank.

It is a further important object 0f this invention to provide an aircharger the operation of which depends upon the action of an eductor, oraspirator, in combination with a float valve and a float therefor.

It is a further important object of this invention to provide an aircharger for maintaining the desired pneumatic pressure within ahydropneumatic tank of a water supply system, the

. operation of the air charger being responsive to the tank pressure andalso to the suction el'fect of a pump supplying water to the tank, andthe air charger mechanism including an eductor operating in accordancewith the now of water under pressure therethrough to draw air into thecharger and expel the charge of air into the tank.

Other and further important objects of this invention will be apparentfrom the disclosure in the specication and the accompanying drawings'.

On the drawings:

Figure 1 is a fragmentary, vertical sectional charger embodying theprinciples of my invention installed in connection therewith, with partsin elevation.

Figure 2 is a similar fragmentary. vertical sectional view illustratingthe air charger at another stage of its operation, with parts in Figure3 is a fragmentary, vertical sectional view, with parts in elevation, ofa modiiled form of my invention.

Figure 4 is a fragmentary, vertical sectional view of a further modifiedform of my invention.

As shown on the drawings:

In Figures `1 and 2, the reference numeral I0 indicates generally ahydro-pneumatic tank in a water supply system such as disclosed in myseat 33.

issued patents, above referred to. Said tank is adapted to be partiallylled with water, as for instance to a normal level indicated by the dotand dash line K, but is here illustrated with the water level at a pointabove said normal lwater level. as indicated by the dotted line J. Air

under pressure is maintained in the space above the water level in thetank.

An air charger of my present invention is indicated generally by 'thereference numeral II. Said air charger I I may suitably comprise acasing I2 having an open anged top I3 adapted to f be closed by a capI4. The lower portion of the .I

casing I2 is provided with a boss I6 having a threaded bore I6 forreceiving the threaded end of a pipe I1 connected to the intake orsuction side of a pump diagrammatically shown at I8. Said pump I8 servesto supply water to the tank I The casing I2 is also connected by a.nipple I9 to the interior of the tank III well below the normal waterlevel K, in order that there may be a constant supply of water underpressure to said casing i2 through'the nipple I8. Alternatively, aseparate source of supply of water under pressure may be introducedthrough the nipple I6 into the casing I2. It is merely a matter ofconvenience to use the water of the hydro-pneumatic tank Il! itself,rather to connect the air charger to a separate source of water underpressure.

The cap It is provided with a central upstanding boss 20, which has abase 2i extending there through, the upper portion of which is threaded,as at 22, for receiving the threaded end of a nipple 23. Said nipple 23is connected by a coupling 2d to a tubing 2b, the other end of which isattached to a. coupling 26 and a threaded nipple 2l'. Said nipple 21 isthreaded into one endk of a check valve assembly indicated generally bythe reference numeral 28, the other end being in iiow communication withthe interior of the tank i8 through the medium of a connection 29.

Said check valve assembly 28 comprises an outer sleeve 290 threaded atboth ends for connection to the threaded end of the nipple 21 and to thethreaded end of the connection 2d. A ball cage 38 is positioned withinsaid sleeve 288 with its reduced threaded end 3i threaded into theinterior threaded bore 32 of said sleeve. Said cage 38 provides a seat33 between an enlarged portion 3d and a reduced portion 35 of the boreextending through said cage. A ball 36 is positioned within saidenlarged bore portion 38 for seating against said seat 33 under theaction of water from the tank IIJ. A pin stop 31 prevents completedisplacement of the bell 36 from the enlarged bore 34 of the cage 30. l

By virtue of the construction of the check valve assembly 28, water fromthe tank I6 cannot pass from the tank into the charger II because waterwill cause the bal136 to oat and seat against the Air, on the otherhand, can pass in either direction through said check valve assembly 28,since it requires a much higher velocity of air flow to cause the valve36 to seat than it does in the case of water. Air is thus free to passin either direction through said check valve assembly 28 in accordancewith the conditions obtaining in the tank I8 and the air charger II, aswill be more fully explained hereinafter.

The casing I2 is divided by a vertical partition III extending down fromthe top thereof to a point spaced from the bottom wall of the casing.Said partition 48 provides a relatively large chamber indicated by thereference numeral II and a relatively small chamber indicated by thereference numeral I2, the latter being in direct flow communication withthe tank I0 through the medium of the nipple Il. 'I'he cap Il isprovided with a threaded opening Il above the chamber 42 for receivingthe threaded end M of a nipple 46 connected to a pressure gauge (notshown) imv indicating the pressure within the tank I0.

Intermediate aligned portions 46 and 41. of the side-wall of the casingI2 and of the partition 40 are enlarged to form a cylindrical opening 48for receiving an eductor 49. Said eductor comprises a casing having acylindrical outer surface and conical innersurfaces convergent towardthe throat portion 68 of the eductor. A transverse aperture 5I vextendsthrough said casing wall at said throat portion 68. Said aperture 6I, asis well understood by those-skilled in the art, func tions to permit theexpiration of fluid from the outside of said casing into the ilow ofiiuid passing through said throat 66, due to the reduction in pressureeffected by the restriction at said throat portion. f

The casing I2 is also formed with a horizontal partition 52, spacedabove the lower wall of said casing to form a shallow chamber 53 andspaced below the bottom edge of the vertical partition d0 to provide apassage 54. Said pasasge 54 forms a flow communication between thechamber tI and an annular chamber 55 surrounding the eductor t9. Saidhorizontal partition 63 further cooperates with an enlargement 58 on theinside of the casing wall to provide a cylindrical aperture 59 forreceiving the discharge end of the eductor d3. Said eductor 49 thusestablishes flow communication between the chambers d2 and 53, and isalso ,in flow communication through the apertures 5i, through theannular chamber 55 with the main chamber 4I.

A oat 66 is mounted within the chamber 4I with its guiding stem portions6I and 62 extendlng through openings 63 and 64 into the bore 2l and intothe chamber 53, respectively. The opening 6d, which is provided in thehorizontal baffle 62, has a resilient liner 65 forming a seat for theupper surface of the valve 66 mounted on the depending end of the lowerstem portion 62. The lower boss I5 is internally apertured as at 61 andthe aperture tted with a resilient sleeve 68 that forms a seat for thelower convex surface of said valve 66. Said .valve 66 thus controls thepassage of fluid-through the aperture 61 into the piping I1. The floatvalve 66 also controls the port 64A between the chambers 4I and 53.

An air intake valve assembly, indicated generally by the referencenumeral 10, is positioned in the lower wall of the casing I2. Said airintake valve assembly 16 comprises a threaded bushing 1I threaded intothe lower wall of the casing I2, as at 12, and provided with a bore 13extending completely therethrough. The upper end of said bore 13 iscounterbored as at 1I and provided with a resilient valve seat 15 forreceiving a ball 16. Said ball 16 has an attached stem 11 that extendsfreely through said bore 13. The end of said stem 11 is enlarged as at16 to prevent complete upward displacementl of said ball 16. Normallythe ball 16 seats upon the seat 15, but when there is a suilicientreduction of pressure within said chamber 4I, the ball raises to admitair through the bore 13 into said chamber. y

The operation of the air charger illustrated in Figures l and 2 will nowbe explained.

When the pump Il is started, assuming the water level in the tank Il tobe that indicated annees a flow of water through the nipple Il into'thechamber 42 and through the eductor 49 into the chamber 53 and outthrough the port 81 into thev pipe I1 leading to the intake of thepumpll.

This iiow of water through the eductor 4 9 creates a reduction inpressure at the throat portion 59. causing water to be inducted throughthe apertures 5| into said throat portion. Water is thus drawn from thechamber 4I and caused to pass through the passage 54 beneath thevertical baille 49 into the annular chamber 55 surrounding the eductor49. This water is drawn into the eductor through the apertures 5| anddischarged, as pre. viously indicated, into the pipe line I1 leading tothe suction side of the pump.

When the water level in the chamber 4| has dropped to a point, such asillustrated in Figure 2, the ball 69 no longer floats and the iloatcontrolled valve S8 seats upon the seat 58 vto close off communicationto the pipe line I1. During the aspiration of the water out of thechamber 4I, however, a suiiicient reduction in pressure occurs to causethe air intake valve 16 to become unseated, to admit air through thebore 13 into the chamber 4|.A Thus, by the time the float control valve66 has closed the opening 61, the chamber 4I has been substantiallyfilled with air.

At this point, with the float control valve 88 seated upon the seat 68,water continues to pass into the air charger from the tank I9 throughthe nipple I9, but now passes out through the apertures 5I and throughthe annular chamber 55 into said chamber 4I to fill the same and at thesame time expel the charge of air from said chamber 4| out through thepipe 25, the check valve assembly 28 and connection 29 back into thetank I9. The chamber 4I is thus left illled with water, ready for thestart of another cycle. So long as the pump continues to operate, thiscycle will be repeated, provided that the water level in the tank I9 isat or above the normal water level indicated by the dot and dash line K.

If the water level in the tank I9 falls below the center line of thevalve assembly 28, say to the level indicated by the dotted line L, thenair will be preferentially drawn in from the tank I9 into the chamber 4|during the operation of the pump I8. This is for the reason that the airin 'the hydro-pneumatic tank I9 is always at slightly above atmosphericpressure, so that air will be drawn in through the check valve assembly28 in preference to being taken in through the air intake valve assembly10. Upon the completion of the cycle, the air taken into the chamber 4|will be expelled back into the tank I9.

Thus, only when the pressure demands of the hydro-pneumatic tank I9requires it is fresh air introduced into the tank from the atmospherethrough the check valve assembly 19.

Figure 3 illustrates a modification of the air charger previouslydescribed, but like the air charger of Figures 1 and 2, that of Figure 3embodies an eductor and oat controlled valve for effecting itsoperation. The modined form of air charger construction, indicated bythe referencev numeral 8l is connected as before to the hydro-pneumatictank I9 at about the normal water lever K therein by means of a htting8|, andl is also connected at a point substantially a below the. normalwater level in the tank I9 by means or a nipple 82.

The air charger I9 comprises a casing 88 providing a main chamber 84.Said iltting-8| is connected to a threaded boss 85 integral with said 19casing 88 and having therethrough an enlarged bore .88 and a reducedthreaded bore 81. A check valve assembly. indicated generally by thereference numeral 88, is mounted in said bore 88 with .the reducedthreaded end 89 thereof threaded into said` reduced threaded boreportion 81. The check valve assembly 88 is similar to that alreadydescribed and includes a ball 99 adapted to seat under water pressureagainst the inclined seat II. Said ball is held against outwarddisplacement by .20 means ofa stop pin 92.

The nipple 82 is connected to the casing 83 by means of an internallythreaded bore 93. A passageway 94 is formed inwardly of the boss 93between the lower wall of the casing 83 and an inwardly extendingpartition 95. A continuation 0f said partition 95 and of the lower wallof the casing 8l forms, as at 95, a downwardly tapered restricted throatof an eductor, indicated generally by the reference numeral 91. Thethrat portion of said eductor 91 is open, as at 98, to provide flowcommunication with the chamber I4. The elongated tapered dischargeportion oi the eductorris formed by the downwardly converging taperedwall 99, which'may be formed integrally with the casing 83, or may beseparately formed. A pipe |99 is connected to the open threaded end |9|of said casing 99 and is also connected to the pump |8 at the intakeside thereof.

The horizontal partition 95 is provided with an opening |92 into whichis fitted a resilient seat bushing |93 having an opening |94therethrough. The internal wall 99 of the eductor 91 is enlarged towardthe lower end thereof to form a restricted *-\\.opening |95, into whichis tted a resilient seat bushing |96 providing an opening |91therethrough. A float |98 is positioned within the chamber 84 with itsdownwardly extending stem |99 passing freely through the openings |94and |81 and through the restricted throat opening 96. The stem portion|99 carries two spaced balls, a small ball I I9 adapted when the float|98 is in its uppermost position to seat against the seat |93, and alarger ball ||I adapted when the oat |98 is in its lowermost position toseat against the seat |95. The stem |99 is of suciently less diameterthan theopenings |94, 95 and |91 to extend freely therethrough andpermit iiuid iiow through these openings.

An air intake valve assembly, indicated generally by the referencenumeral |I2 is positioned in the lower wall of the casing 83. Saidassembly comprises a casing I I3 having a threaded end I I4 threadedinto an opening I I5 in said lower casing wall. Said casing I I 3 isprovided with a bore I I6 extending completely therethrough andterminating at its upper end in a counterbored portion I1. A resilientseat I I8 is fitted in said counterbore |I1. The valve proper comprisesa ball II9 adapted to seat on the seat I I8 and having a stem DOrtion|29 extending downwardly through said bore |I5 and terminating in'anenlarged end I2I.

The operation of the air charger mechanism illustrated in Figure 3 maybe described as follows:

When the level of the water within the tank I is at or above the dot anddash line K, the

ball 90 of the check valveassembly 32 will be in its seated position;chamber 34 will be substan tlally filled with water and the iioat |08will be in its raised position as illustrated in Figure 3, leaving thelower valve opening III open while maintaining the upper valve |34closed by the ball H0.

When the pump |8 is started up, water will be caused to ow from the tankIl through the nipple 82 and passage 94 down through the throat 95 ofthe eductor 91. Because of the reduced pressure at the throat portion ofthe eductor, water will be drawn from the chamber 84 through the opening98 into said throat portion to be discharged downwardly into the pipe|00 leading to the intake oi the pump |8. The oat |08 will remain in itsfloating position until the water level in the chamber 84 dropssufciently to be no longer able to buoy up said float.

During the continued ow of the water through the eductor 91, a reductionin pressure takes place within the chamber 84, with the result that theair intake valve ball ||9 lifts off of its seat to permit air to bedrawn into said chamber. When the iloat |08 reaches its lowermostposition, the larger ball closes oil' the valve passage |01 to stop theiiow of water into the pipe |00.

Thereupon the water iiowing from the tank I0 through the nipple 82 andpassageway 94 iiows up th-rough the upper valve port |04, the ball I0 inthis position being unseated, and out through the throat opening 98 intothe chamber 84. In iiowing into the chamber 84, the water expels thecharge of air through the valve assembly 88 and through the tting 8|back into the tank i0. The cycle is repeated as often as the pump I8A isstarted up, provided that the water level in the tank I0 is at or abovethe level indicated by the dot and dot and dash line K. When the waterlevel is below that level, as for instance at the level indicated by thedotted line L, air merely is drawn in from the tank I0 and then forcedback into the tank, the same as previously described.

In Figure 4, there is illustrated a further modification of my inventionin which the referance numeral |25 indicates generally this modied formof air charger. As before. the air charger |25 is connected to the tankl0 at about the normal water level therein, as indicated by the dot anddash line K, through a iitting |26 and a check valve assembly |21. Theair charger |25 is also connected at a lower point to the tank |0through a nipple and fitting |28. Said air charger |25 comprises acasing |29 which is divided internally by a horizontal partition |30into an upper chamber |3| and a lower chamber |32.

Said partition |30 and a continuation of th wall of the casing |29provide a throat and discharge portion |33 and |34, respectively, of aneductor indicated generally by the reference numeral |35. The intake andconstricted portions of said eductor |35 are provided by a tube |38threaded into an opening |31 in the wall o! said casing |29. Said tube|35 is threaded at its outer end, as at |38, to receive the threaded endof the nipple |28, and at its inner end is provided with inwardlytapering walls |39 providing a restricted throat portion |40 that iscoaxially aligned with the throat portion |33. An annular passage |4| isformed between the conformingly tapered walls of said constrlctedportions |30 and |33.

A check valve assembly |42 is mounted in the lower wall |43 of an upperoiiset portion |44 of said casing |29. Said check valve assembly |42includes a valve proper comprising a ball |45, adapted to seat upon aseat |48 and provided with a stem portion |41 freely extending through abore |48 in said assembly. The lower end of said stem |41 is providedwith an enlargement |49 to prevent complete upward displacement of saidvalve.

The casing |29 is connected through the lower wall, as at |50 to a pipe|5| leading to the intake side of the pump I8. A valve seat |52 isprovided in the lower wall portion |50 for receiving a valve |53controlled by a iloat |54. Said rloat |54 has a stem |55 which ispivoted, as at |55, to ears |51 attached to the inside of the casingWall. The valve |83 is pivotally suspended by means of a stm portion |58from the float stem |55, as at 9.

The operation of the air charger illustrated in Figure 4 is as follows:

When the level of the water within the tank I0 is at or above the normalwater level indicated by the dot and dash line K, the ball |50 of thecheck valve assembly |21 is seated to prevent the iiow of water into thechamber |3| At the time the pump |0 starts up, the chambers |3| and |32are both filled or substantially filled with water, since they are inopen communication through the nipple |28 with the water in the tank l0and therefore under tank pressure. The oat |54 would therefore be in itselevated position, with the valve |53 unseated. Upon starting up thepump, the valve |53 being open, the suction effect of the pump drawswater from the chamber |32 andcreates a reduced pressure therein,causing water under tank pressure to be forced through the eductor |35and to draw along with it water from the chamber |3|. As the water levelin the chamber |3| is lowered, air is drawn in through the check valveassembly |42 by reason of the drop in pressure. This continues untilmost of the water 1s drained out ot chamber |3|. The action of theeductor |35 is then to draw air or air and water from the chamber |3|,where the air separates from the water. Ultimately the level of thewater in the lower chamber |32 drops suiciently to be no longer able tomaintain the float |54 in its elevated position. Said oat thereupondrops and seats the valve |53 upon its seat |52 to close off the piping|5| to the suction side of the pump.

At this point, water continues to flow from the tank through the nipple|28 into chambers |32 and |3| to fill these chambers. The valve |53remains seated by reason of the difference in pressure between that inthe chamber |32 and that in the suction line to the pump I8. The waterwill continue to run through the jet |35 until the pressure within thefront Achamber |32 and upper chamber |3| becomes equal to the tankpressure, at which time the flow of water through the jet will cease.The charge of air drawn into the chambers through the intake valveassembly |42 will, during this stage, .be displaced through the checkvalve assembly |21 and the ttlng |28 into said tank l0, due to thelightness of the air relative to the water and to the fact that the airis below the water level in the tank. The cycle is again ready to berepeated when the pump |8 starts up.

It will thus be seen that all modifications of sans the 1r-einiger'.nereiniambedem- A body the",saineprinciple,` namely one based upon thefunction" of an eductor or aspiratorto draw iluid into the. reducedthroatjportion during its operation.'1n each instance wateris withdrawnfrom the air charger `by theV` action of the eductor until 'the 'level`bf Ywater therein vhas dropped suiiiciently to, cause a float todrop andclose a valve operated.l thereby `to kshut oi! piping `leading *to thesuctionside of thepunip.` During this removal of water fronrthe airohargena reduction in pressure is set jupk that results in the drawingin o! air from the'atmosphere to replace the water.` Upon vthe closingofi of the pipe leading to the suction side of thepump, water stillcontinues to pass into the eductor, but instead of any eductionactionoccurring, the water spills out through fthe throat openinginto the aircharger to 'displace' the air valready drawn in and therebyexpelsuchcharge o! air into the tank itself." IZl'heprovision oi.' a check' valveVcapable of Apassing air in 'eitherdirection but not of passing wateri`from the tank into the air charger makes possible this automaticoperation of my air. charger to introduce a charge'of air into the tankwheneverthe pressure of the ytank is below a predetermined pointandwhenever the pump for supplyingwater to the tank vis starteduup.

It Vwill of course be understood that various details of constructionmay be varied through a wide' range without departing from theprinciples of this invention and it is, therefore, not the purpose tolimit the patent granted hereon otherwise than necessitated by thevscope of the appended claims. f

I claim as my invention:

1. An air charger for. `maintaining pneumatic pressure in ahydro-pneumatic tank in response to the tank pressure and the suctioneffect of the Pump supplying water to -said tank, said chargercomprising a casing having an opening for connection to said tank and tosaid pump intake, an air intake into said casing, a Venturitypeaspirator operable upon a flow of water therethrough to draw water outof said casdrawing air thereinto and finally for expelling said airthrough said check valve-controlled' opening for connection to saidtank.

3. An air charger for maintaining pneumatic pressure in ahydro-pneumatic tank in response to the tank pressure and the suctioneil'ect of the pump supplying water to said tank, said chargercomprising a casing having a chamber therein and an opening forconnection to said tank. a check valve for control of said opening forpermitting air ilow therethrough in either direction but not water nowfrom `said tank, a valve controlled air intake into said chamber, saidcasing having an opening for connection to a source of water underpressure and having an opening for connection to the suction side ofsaid pump, a Venturi-type aspirator in flow communication between saidlast two openings and having a low pressure'opening into said chamber, afloat controlled valve controlling said opening for said pump intakeconnection and a iloat in said chamber controlling said valve to openthe same when said chamber is nlled with water and to close ing and airthrough said air intake into said casing, and a iloat controlled valveoperable upon said casing being substantially lled with air to closesaid opening for connection to said pump intake. whereupon continuedilow of water through said aspirator lls said casing with water forexpelling air therefrom into said tank.

2. An air charger for maintaining pneumatic pressure in ahydro-pneumatic tank in response to the tank pressure and the suctioneffect of the pump supplying water to said tank, said charger comprisinga casing having a chamber therein and an opening for connection to saidtank, a check valve for control of said opening for permitting air ilowtherethrough in either direction but not water ow from said tank, avalve controlled air intake into said chamber, said casing having anopening for connection to a source of water under pressure and anopening for connection to the suction side of said pump, a Venturi-typeaspirator in flow communication between said last two openings andhaving a low pressure opening into said chamber, a iloat controlledvalve controlling said opening for said pump intake connection and afloat controlling said valve to open the same when said chamber Y islled with water and to close the same when said chamber is substantiallyiilled with air, the flow oi water through said aspirator serving fordrawing water from said chamber and for the same when said chamber issubstantially filled with air, the ilow of water through said aspiratorserving to draw water from said chamber and to draw air thereinto andinallyrKto expel air through said check valve controlled opening fordischarge into said tank.

4. An air charger for maintaining pneumatic pressurev in ahydro-pneumatic tank in response to the tank pressure and the suctioneiect of the pump supplying water to said tank, said charger comprisinga casing having a ilrst opening for connection to said tank at about thenormal water level therein, a second opening for connection to a supplyof water under pressure, a third opening for connection to the suctionside of said pump and a valve controlled intake for taking ambient airinto a chamber of said casing, a check valve for control of said rstopening for permitting air ow in either direction but n'ot water flowfromv said tank into said chamber, a float controlled valve controllingsaid third opening, a Venturi-type aspirator in ilow communicationbetween said second and third openings and having a throat connection tosaid chamber, and a oat in said chamber for actuating saidiloat-controlled valve to close said third opening when said chamber issubstantially filled with air and to open said third opening when saidchamber is filled with water.

5. An air charger for maintaining pneumatic pressure in ahydro-pneumatic tank in response to the tank pressure and the suctione'ect of the pump supplying water to said tank, said air chargercomprising a casing providing a chamber having openings for connectionto said tank and to the intake of said pump, a float within said chamberhaving a valve attached thereto for controlling said pump intakeopening, an air intake valve for admitting air into said chamber, saidchamber having one of said openings near the top thereof forcheck-valve-controlled connection for discharge into said tank forpermitting the passage of air in either direction but not ilow of waterfrom said tank to said chamber, a Venturi-type aspirator associated withsaid chamber and operable by the ilow of water under pressuretherethrough for drawing air through said intake valve into said chamberand subsequently on the closing of said iloat controlled valve fordisplacing said air through said check valve controlled opening fordischarge into said tank.

6. An air charger for maintaining pneumatic pressure in ahydro-pneumatic tank in response to the tank pressure and the suctioneffect oi the pump supplying water to said tank, said charger comprisinga casing providing a chamber having a irst opening for connection tosaid tank, a second opening for connection to a supply of water underpressure, a third opening for connection to the suction side of saidpump and a valve controlled air intake, a check valve for controllingsaid first opening for permitting air ow in either direction but notwater flow from said tank to said chamber, a float controlled valvecontrolling said third opening, a Venturitype aspirator associated withsaid chamber and said second opening and operable by the. ilow of saidwater under pressure therethrough for drawing air into said chamberthrough said intake valve and upon the closing of said float controlledvalve for displacing said air through said check valve controlled ilrstopening for discharge into said tank. l

7. An air charger system for maintaining pneumatic pressure within ahydro-pneumatic tank in response to tank pressure and the suction eiIectof the pump supplying water to said tank, said charger comprising acasing having an opening for connection to said tank at about the normalwater level therein and also at a level below the normal water level andan opening for connection to said pump intake, an air intake and aVenturi-type aspirator associated 4with said casing and operative on thepressure now of water through said Venturi-type aspirator for drawingair into the system through said air intake when the water level isabove said normal water level opening and for causing the air so drawnin to pass through said last mentioned opening for discharge into saidtank.-

Air charger for maintaining pneumatic pressure in a hydro-pneumatic tankin response to tank pressure and the suction effect of the 12 pumpsupplying water to said tank, said .charger comprising a casing having avalve-controlled intake, means associated with. said casing deilning awater flow passage for lconnection at one end to the tank and at theother end to the suction side of the pump, a Venturi-type aspiratorconstituting a part of said passage and having a constricted throat andan opening from said throat into said casing interior to draw water outot and air into said casing interior when .water ilows through saidpassage, and a float con trlled valve operable upon said casing interiorbeing substantially` iilled with air to close the end of said passage tosaid suction side of the pump, whereupon continued ilow of water throughsaid aspirator illls said casing with water expelling air therefrom forpassage into said tank.

9. An air charger for maintaining pneumatic pressure in ahydro-pneumatic tank in response to the tank pressure and the suctioneffect of a pump supplying water to said tank, comprising a casinghaving an opening for connection to said tank and to said pump intake,an air intake into said casing, a Venturi-type aspirator. operable upona flow of water from said tank therethrough to draw air through said airintake into said casing, and a iloat controlled valve operable upon saidcasing being substantially iilled with air to close said opening forconnection to said pump intake, whereupon water ows from said tank intosaid casing to displace the body of air from within said casing intosaid tank.

ARTHUR W. BURKS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,172,057 Burks Sept. 5, 19392,172,097 Burks Sept. 5, 1939

